Weapon fire detection and localization can be accomplished using a variety of sensing modalities. Typical modalities include radar, acoustic, electro-optic, or some combination of these. Electro-optical solutions typically exploit projectile launch blast, thermal radiation of in-flight round, and the thermal radiation of rocket motors of missiles and rockets. Electro-optical solutions are often employed for close range small arms and unguided projectile detection. Additionally, air-systems have employed electro-optical sensors for long range weapons fire detection systems such as missile warning systems. For systems detecting weapons fired air-to-air or air-to-ground, atmospheric signal degradation is less impactful than for systems which detect ground-to-ground weapons fire. Long range electro-optical weapons fire detection systems for ground application must be able to handle complications due to atmospheric signal degradation and near field clutter sources.
Electro-optical weapons fire detection systems for ground application, capable of detecting short and long range threats require complex detection methodologies to accurately detect weapons fire over a broad dynamic range of signal intensity. When a high intensity weapon signature is available, as when the launch is near the sensor, simple thresholds can be used to detect weapon fire while minimizing clutter sources. Long range electro-optical weapons fire detections often involve severely reduced signature intensities due to atmospheric degradation. Additionally, near field motion can generate clutter sources of similar intensities to far field weapons fire. A complex detection algorithm is required to differentiate actual weapons fire signatures of various intensities from cluttered backgrounds while providing acceptable detection rates.